Roleplaying for the sole purpose of trolling. One who trollplays would be known as a trollplayer.
A user named Albert_Wesker is posting on an Resident Evil board and insists that Leon should be killed off in the next game? He's definitely trollplaying.
The act of logging into an online role-playing environment with the express intention of annoying role playing geeks
and possibly making them cry.
Robero the Valiant: Good day villager, perhaps you could direct us to the nearest Ale House?
Villager NPC: Sure, go right down this path...
Gandarb: I kill the villager, scalp him, and hand the bloody scalp to Robero.
Robero the Valiant: (out of character) Wat r u doing!?!1
Gandarb: What, that's what my character would do!
Robero the Valiant: (out of character) You're Troll Playing!